Megger OTS60SX/2 - Semi Automatic Oil Test Set

The Megger OTS60SX/2 oil test set is suitable for field use and can be powered from a range of mains supplies. The maximum 60kV output allows tests to be performed on oil from a wide variety of electrical installations including transformers, circuit breakers and other equipment. The operation of the test set is extremely simple and the results are displayed on a bright LED display. A selection of vessels allows the instrument to be configured for a variety of test standards.

The microprocessor controlled, semi automatic operation allows the user to select a choice of voltage rise rates as specified in many national standards. The start button will then initiate the test. If oil breakdown occurs the instrument will remove the test voltage and display the breakdown value. Alternatively the user can pause the test voltage at any time to carry out a withstand test. The voltage will be maintained at this level for one minute or until breakdown. After one minute the voltage will automatically continue to rise until breakdown occurs or to the maximum output of the instrument.

A sheet steel enclosure makes the instrument rugged and safe. A strong polycarbonate window covers the high voltage chamber. A mesh screen enables the oil breakdown to be viewed and reduces electro-magnetic emissions. Operator safety is ensured by an interlock on the chamber door. The power cord and other accessories are stored in a pouch which is fitted to the side of the test set.

The oil vessel is located in the top of the instrument. An external nut varies the electrode gap. The design of the vessels and test chamber makes them easy to clean. The instrument is supplied with a spacing gauge for setting the electrode gap.

Mains Input Panel

Operation:

Oil Sampling - The relevant test specification will give advice on the best methods to use when sampling oil.  Contamination of the oil may lead to misleading results. Always run off a small amount of oil before sampling and ensure that the flow of oil is steady.

Optional vessels are available for testing to national specifications. Some specifications require stirring of the oil sample as well as different test electrode shapes. Once the correct vessel has been chosen for the required test the electrode gap should be set. This is achieved by adjusting the threaded nut on the side of the vessel. Small adjustment of the gap can be made by hand tightening the nuts and rotating the spindle. A slot is provided on the end of the spindle for this purpose.

Preparing the Oil Test Vessel - A set of individual 0,5 mm feeler gauges is provided for accurate measurement of the gap. Gauges can be combined to measure from 1 mm to 4 mm. (see page 12)

Clean the vessel in accordance with the instructions given in the relevant test specification. Allowing space for the lid to be fitted, fill the vessel with the oil sample. The amount of oil required will depend upon the type of lid used. Load the vessel in the test chamber, connecting the motor power cable, if fitted, and carefully shut the door so that the safety interlock switch operates.

Operation:

Control Panel - The control panel contains the supply on/off switch, the high voltage display, voltage ramp rate selection and the three control keys. The operation of the instrument is very simple. When the instrument is turned on, the on/off switch is illuminated, and the software edition code will be flashed up on the display.

Breakdown Testing - The suitable ramp rate for the test to be performed should be selected using the ‘’ key. The START key"" will then turn on the high voltage. The red H.V. indicator will light to show the output voltage is on. The voltage will then increase at the selected ramp rate and the corresponding value will be shown on the display. If oil breakdown occurs the instrument will detect this and immediately shut off the high voltage. The breakdown voltage value will be left on the display until the next test is started. If no breakdown occurs, the high voltage will rise to 60 kV. At this point the test voltage is cut off and this maximum value left on the display.

A test can be stopped at any time by pressing the STOP"" button. This will remove the high voltage from the oil sample and leave the display at 0,0 kV.